1. Field of the Invention
The present invention is broadly concerned with the improved processing equipment designed to rapidly handle, imprint, die cut and transfer sheet-type blanks and especially relatively thick corrugated blanks. More particularly, the invention is concerned with such equipment, and corresponding methods, wherein blanks are successively fed along a generally horizontal path through a printing station and then through handling equipment; at this point a movable pickup member is employed for lifting and delivering the blanks to the open platens of a clamshell die cutter. After cutting, a removal assembly picks up the processed blanks and delivers them to an outfeed conveyer for downstream processing.
2. Description of the Prior Art
Clamshell die cutters have long been available and used in the paper converting industry. Generally speaking, clamshell die cutters include a relatively massive frame supporting a pair of platens. Normally, one platen is stationary whereas the other is moved through an arcuate path between a full open position allowing a blank to be placed on the platen, to a cutting position where the blank is die cut. One of the platens carries a cutting die so that, when the movable platen is closed, an accurate die cut is achieved.
In typical operations with clamshell die cutter, an operator stands near the device and manually removes a cut blank from the opened platen and then places a fresh uncut blank thereon. This is of course an extremely labor-intensive undertaking, given that the operator must constantly attend the die cutter and insure that each individual blank is placed in perfect alignment for proper cutting. Moreover, any carelessness on the part of the operator quickly leads to a relatively serious industrial accident, where the operator inadvertently leaves his hand or arm between the platens as they close.
It has been proposed in the past to provide automatic feeders for clamshell die cutters. One such design incorporates an elevator wherein a stack of blanks is successively elevated and delivered into the die cutter. However, such elevator units have only a limited blank capacity and thus must be reloaded on a frequent basis. For example, where corrugated blanks are processed, the elevator feeder can accommodate only about 150 blanks. This means that the feeder must be reloaded approximately every 7 minutes.
High throughput die cutting devices have also been used in the past which differ fundamentally from clamshell cutters. These units operate by moving a die-carrying platen in a reciprocal, up-and-down fashion. With these die cutters, blanks are successively fed between the opened platens, and are die cut as the upper platen moves downwardly; the cut blanks are then removed from the platen assembly for further processing. While die cutters of this variety are capable of high speed operation even when corrugated blanks are processed, they are extremely expensive as compared with clamshell die cutters.
There is accordingly a need in the art for improved blank processing equipment making use of a relatively inexpensive clamshell die cutter while nevertheless achieving the high operating speeds of reciprocal die cutters.
The present invention overcomes the problems outlined above and provides processing equipment in the form of a station including a clamshell die cutter and a feeding device operable to feed individual feedstock blanks into the clamshell cutter when the latter is open, with the feeding device comprising a transfer mechanism for individually shifting respective blanks from a stack thereof toward the die cutter, and a pickup member that moves cut blanks from the feeding device to the die cutter when the latter is open. Preferably, the overall station includes a printing assembly designed to print each successive blank, together with a cut blank removal assembly designed to pick up a cut blank from the die cutter for transfer and downstream processing.
Preferably, the transfer mechanism comprises a reciprocal pusher plate operable to engage and shift the bottom most blank from a stack thereof along with a transfer belt presenting a generally horizontal upper run orientated to receive the blank and deliver the same for pickup. The printing assembly is advantageously located between the pusher plate and the transfer belt. The preferred pickup is vacuum-operated and includes a shiftable arm operated in timed relationship with the pusher plate and transfer belt. The blank removal assembly likewise includes a vacuum pickup member, supported on arms so that it is moved from a pickup position adjacent the clamshell die when the latter is open, and a delivery position.